"Elseworlds, Part 2" contained a ton of Easter Eggs - from the ('60s TV series-referencing) bust of Shakespeare to our heroes getting pinched on the corner of "Nolan and Burton" - but the truly devilish ones came within the walls of Arkham.

After that, we're led to Basil Karlo (aka original recipe Clayface)...

..and then a Riddler-style riddle. I guess Riddler's just allowed to mark up the joint however he feels.

And here's the door for Edward Nygma himself. It's so quick though. Is that Nigma spelled with an "I?"

"Guggenheim, M" is an egg, for sure, but it's a nod to Arrowverse EP Marc Guggenheim. AKA The Sinister Showrunner.

Lesser-known baddie Psycho-Pirate was on the scene, donning his gold mask, which was apparently easy to find once the inmates were set free. Maybe he just has to hang it up on a hook outside his cell.

As it turns out, villainous accessories were everywhere. Just stored away for safe (?) keeping. Here's, possibly, Captain Boomerang's weapon. Though that character already exists/existed in the Arrowverse. A non-insane version. And are those... penguin grenades? We choose to believe it so.

Up on the shelf in the store room is a very Dark Knight-looking version of Bane's mask, some sunglasses, and fake teeth (or real teeth in gross teeth water). Maybe, for the latter, a Joker nod? Since the Clown Prince of Crime is off limits on TV like Batman (for now anyway).

While Victor Fries (Mr. Freeze) himself doesn't make an appearance, some condensed nitrogen and his freeze gun sure do!

And what sort of asylum riot would it be without some of Scarecrow's toxin? A run-of-the-mill boring one without deadly manifestations of people's fears, that's what kind.

Arkham Asylum Easter Eggs on Arrow

"Elseworlds, Part 2" contained a ton of Easter Eggs - from the ('60s TV series-referencing) bust of Shakespeare to our heroes getting pinched on the corner of "Nolan and Burton" - but the truly devilish ones came within the walls of Arkham.